2015-07-29 - Release 3.8.11.1

SQLite version 3.8.11.1 is a patch release that fixes two arcane
issues that were reported shortly after 3.8.11 was released. Upgrade
from 3.8.11 only in the unlikely event that one of these obscure
issues affect your code.

2015-07-27 - Release 3.8.11

SQLite version 3.8.11 is a regularly scheduled maintenance release.
See the change log for details.

2015-05-20 - Release 3.8.10.2

Yikes! Index corruption after a sequence of valid SQL statements!

It has been many years since anything like
this bug has snuck into
an official SQLite release. But for the pasts seven months
(version 3.8.7 through version 3.8.10.1)
if you do an INSERT into a carefully
crafted schema in which there are two nested triggers that convert
an index key value from TEXT to INTEGER and then back
to TEXT again, the INTEGER value might get inserted as the index
key instead of the correct TEXT, resulting in index corruption.
This patch release adds a single line of code to fix the problem.

If you do actually encounter this problem, running REINDEX on the
damaged indexes will clear it.

There is no reason to upgrade from version 3.8.10 unless you are
using the new SQLITE_ENABLE_DBSTAT_VTAB compile-time option.

2015-05-07 - Release 3.8.10

SQLite version 3.8.10 is a regularly scheduled maintenance release.
This release features performance improvements, fixes to several
arcane bugs found by the AFL fuzzer, the new "sqldiff.exe" command-line
utility, improvements to the documentation, and other enhancements.
See the release notes for
additional information.

2015-02-25 - Release 3.8.8.3

The 3.8.8.3 patch release fixes an obscure problem in the SQLite code
generator that can cause incorrect results when the qualifying expression
of a partial index is used inside the ON clause of a LEFT JOIN.
This problem has been in the code since support for partial indexes
was first added in version 3.8.0. However, it is difficult to imagine
a valid reason to every put the qualifying constraint inside the ON
clause of a LEFT JOIN, and so this issue has never come up before.

Any applications that is vulnerable to this bug would have encountered
problems already. Hence, upgrading from the previous release is optional.

2015-01-30 - Release 3.8.8.2

The 3.8.8.2 patch release fixes a single minor problem: It ensures
that the sqlite3_wal_checkpoint(TRUNCATE) operation will always truncate
the write-ahead log even if log had already been reset and contained
no new content. It is unclear if this is a bug fix or a new feature.

Something like this would normally go into the next regularly scheduled
release, but a prominent SQLite user needed the change in a hurry so
we were happy to rush it out via this patch.

2015-01-20 - Release 3.8.8.1

Within hours of releasing version 3.8.8, a bug was reported against
the 10-month-old 3.8.4 release. As that bug exists in all subsequent
releases, the decision was made to issue a small patch to the
3.8.8 before it came into widespread use.

2015-01-16 - Release 3.8.8

SQLite version 3.8.8 is a regularly schedule maintenance release of
SQLite.

There are no dramatic new features or performance enhancements in this
release, merely incremental improvements. Most of the performance gain
in this release comes from refactoring the B-Tree rebalancing logic to
avoid unnecessary memcpy() operations. New features include the
PRAGMA data_version statement and the ability to accept a
VALUES clause with no arbitrary limit on the number of rows.
Several obscure bugs have been fixed, including some multithreading
races and a work-around for a compiler bug on some Macs.

2014-12-09 - Release 3.8.7.4

This release fixes adds in a mutex that is required by the changes of
the 3.8.7.3 patch but was accidentally omitted. The mutex was not required
by any of the internal SQLite tests, but Firefox crashes without it.
Test cases have been added to ensure that mutex is never again missed.

2014-12-06 - Release 3.8.7.3

This release fixes two obscure bugs that can result in incorrect
query results and/or application crashes, but not (as far as we can
tell) security vulnerabilities. Both bugs have been latent in the
code across multiple prior releases and have never before been encountered,
so they are unlikely to cause problems. Nevertheless
it seems prudent to publish fixes for them both. See the
change log for details.

2014-11-19 - Release 3.8.7.2

SQLite version 3.8.7.2 is a patch and bug-fix release. Changes from
the previous release are minimal.

The primary reason for this release is to enhance the ROLLBACK command
so that it allows running queries on the same database connection to
continue running as long as the ROLLBACK does not change the schema.
In all previous versions of SQLite, a ROLLBACK would cause pending
queries to stop immediately and return SQLITE_ABORT or
SQLITE_ABORT_ROLLBACK. Pending queries still abort if the ROLLBACK
changes the database schema, but as of this patch release, the queries
are allowed to continue running if the schema is unmodified.

In addition to the ROLLBACK enhancement, this patch release also
includes fixes for three obscure bugs. See the
change log for details.

2014-10-30 - Release 3.8.7.1

The primary reason for this bug-fix release is to address a problem with
updating the value of fields at the end of a table that were added
using ALTER TABLE ADD COLUMN. This problem
1 first appeared in the
3.8.7 release.

Another minor annoyance in the 3.8.7 release was the fact that the
Android build tried to use the strchrnul() function from the standard
C library but that function is not available on Android. Android builds
had to add -DHAVE_STRCHRNUL=0 to work around the problem. This patch
fixes that so that Android builds should now work without any changes.

The operation of PRAGMA journal_mode=TRUNCATE has been enhanced so that
it invokes fsync() after truncating the journal file when
PRAGMA synchronous=FULL. This helps to preserve transaction durability
in the case of a power loss occurring shortly after commit.

Finally, a couple of long-standing and obscure problems associated with run
UPDATE and DELETE on VIEWs were fixed.

2014-10-17 - Release 3.8.7

SQLite version 3.8.7 is a regularly scheduled maintenance release.
Upgrading from all prior versions is recommended.

Most of the changes from the previous release have been micro-optimizations
designed to help SQLite run a little faster. Each individual optimization
has an unmeasurably small performance impact. But the improvements add up.
Measured on a well-defined workload (which the SQLite developers use
as a proxy for a typical application workload) using cachegrind on Linux
and compiled with gcc 4.8.1 and -Os on x64 linux, the current release
does over 20% more work for the same number of CPU cycles compared to the
previous release. Cachegrind is not a real CPU, and the workload
used for measurement is only a proxy. So your performance may vary.
We expect to see about half the measured and reported improvement in
real-world applications. 10% is less than 20% but it is still pretty
good, we think.

This release includes a new set of C-language interfaces that have
unsigned 64-bit instead of signed 32-bit length parameters. The new
APIs do not provide any new capabilities. But they do make it easier
to write applications that are more resistant to integer overflow
vulnerabilities.

This release also includes a new sorter that is able to use multiple
threads to help with large sort operations. (Sort operations are
sometimes required to implement ORDER BY and/or GROUP BY clauses and
are almost always required for CREATE INDEX.) The multi-threads sorter
is turned off by default and must be enabled using the
PRAGMA threads SQL command. Note that the multi-threaded sorter
provides faster real-time performance for large sorts, but it also
uses more CPU cycles and more energy.

2014-08-15 - Release 3.8.6

SQLite version 3.8.6 is a regularly scheduled maintenance release.
Upgrading from all previous versions is recommended.

This release contains the usual assortment of obscure bug fixes.
One bug, however, deserves special attention.
A problem appeared in the CREATE INDEX command beginning with
version 3.8.2 (2013-12-06) that allowed, under some circumstances,
a UNIQUE index to be created on a column that was not unique. Once
the index was created, no new non-unique entries could be inserted, but
preexisting non-unique entries would remain. See ticket
9a6daf340df99ba93c
for further information. In addition to fixing this bug, the
PRAGMA integrity_check command has been enhanced to detect
non-uniqueness in UNIQUE indices, so that if this bug did introduce
any problems in databases, those problems can be easily detected.

Version 3.8.6 uses 25% fewer CPU cycles than version 3.8.0 from
approximately one year ago, according to valgrind
and the
test/speedtest1.c
test program.
On the other hand,
the compiled binary for version 3.8.6 is about 5% larger than 3.8.0.
The size increase is
due in part to the addition of new features such as WITHOUT ROWID
tables and common table expressions.

2014-06-04 - Release 3.8.5

SQLite version 3.8.5 is a regularly scheduled maintenance release.
Upgrading from the previous version is recommended.

Version 3.8.5 fixes more than a dozen obscure bugs. None of these
bugs should be a problem for existing applications. Nor do any of
the bugs represent a security vulnerability. Nevertheless, upgrading
is recommended to prevent future problems.

In addition to bug fixes, the 3.8.5 release adds improvements to the
query planner, especially regarding sorting using indices and handling
OR terms
in the WHERE clause for WITHOUT ROWID tables. The ".system" and
".once" dot-commands were added to the command-line interface. And
there were enhancements to the FTS4 and RTREE virtual tables. See
the change log for details.

2014-04-03 - Release 3.8.4.3

The optimizations added in version 3.8.4 caused some queries that involve
subqueries in the FROM clause, DISTINCT, and ORDER BY clauses, to give an incorrect
result. See
ticket 98825a79ce145
for details.
This release adds a
one-character change
to a single line of code to fix the problem.

2014-03-26 - Release 3.8.4.2

The code changes that resulted in the performance improvements
in version 3.8.4 missed a single buffer overflow test, which could
result in a read past the end of a buffer while searching a database
that is corrupted in a particular way. Version 3.8.4.2 fixes that
problem using a
one-line patch.

We are not aware of any problems in version 3.8.4
when working with well-formed database files. The problem fixed by this
release only comes up when reading corrupt database files.

Both of these issues came to light within minutes of tagging the previous
release. Neither issue is serious but they can be annoying. Hence, the
decision was made to do a quick patch release to address both issues.

2014-03-10 - Release 3.8.4

SQLite version 3.8.4 is a maintenance release featuring performance
enhancements and fixes for a number of obscure bugs.
There are no significant new features in SQLite version 3.8.4.
However, the number of CPU cycles (measured by valgrind) needed to
do many common operations has be reduced by about 12% relative to the
previous release, and by about 25% relative to version 3.7.16
from approximately one year ago.

Version 3.8.4 of SQLite fixes several corner-case bugs that were
found since the previous release. These bugs were unlikely to appear
in practice, and none represent a security vulnerability.
Nevertheless, developers are encouraged to upgrade from all prior releases.

2014-02-11 - Release 3.8.3.1

SQLite version 3.8.3.1 fixes a bug present in versions 3.8.1,
3.8.2 and 3.8.3 that can cause queries to omit valid output rows.
Upgrading from those versions is recommended.

The problem only comes up if SQLite is compiled with either the
SQLITE_ENABLE_STAT3 or SQLITE_ENABLE_STAT4 compile-time options.
In that case, if a query has a WHERE clause that contains expressions
like this:

WHERE (expr1 OR expr2 OR ... OR exprN) AND column IS NOT NULL

Where all of expr1 through exprN are suitable for use by indexes,
then during query planning SQLite might mistakenly converted
the "column IS NOT NULL" term into "column>NULL". But the latter
term is never true, and so the query would return no rows.

The trouble ticket for this bug is
[4c86b126f2].
It is recommended that all users upgrade to avoid this problem.

2014-02-03 - Release 3.8.3

SQLite version 3.8.3 is a regularly scheduled maintenance release.
Upgrading from the previous release is optional.

This release also includes many small performance enhancements which
should give a small speed boost to legacy applications. And there are
other minor enhancements such as the addition of the printf() SQL
function. See the change log for details.

2013-12-06 - Release 3.8.2

SQLite version 3.8.2 is a regularly scheduled maintenance release.
Upgrading from the previous release is optional.

Version 3.8.2 adds support for WITHOUT ROWID tables. This is a
significant extension to SQLite. Database files that contain WITHOUT ROWID
tables are not readable or writable by prior versions of SQLite, however
databases that do not use WITHOUT ROWID tables are fully backwards
and forwards compatible.

The 3.8.2 release contains a potentially incompatible change. In
all prior versions of SQLite, a cast from a very large positive
floating point number into an integer resulted in the most negative integer.
In other words, CAST(+99.9e99 to INT) would yield -9223372036854775808.
This behavior came about because it is what x86/x64 hardware does
for the equivalent cast in the C language. But the behavior is
bizarre. And so it has been changed effective with this release so that
a cast from a floating point number into an integer returns the integer
between the floating point value and zero that is closest to the floating
point value. Hence, CAST(+99.9e99 to INT) now returns +9223372036854775807.
Since routines like sqlite3_column_int64() do an implicit cast if the
value being accessed is really a floating point number, they are also
affected by this change.

Besides the two changes mentioned above, the 3.8.2 release also
includes a number of performance enhancements. The
skip-scan optimization is now available for databases that have been
processed by ANALYZE. Constant SQL functions are now factored out of
inner loops, which can result in a significant speedup for queries that
contain WHERE clause terms like "date>datetime('now','-2 days')". And
various high-runner internal routines have been refactored for reduced
CPU load.

2013-10-17 - Release 3.8.1

SQLite version 3.8.1 is a regularly scheduled maintenance release.
Upgrading from the previous release is optional, though you should upgrade
if you are using partial indices as there was a
bug related to partial
indices in the previous release that could result in an incorrect answer
for count(*) queries.

The next generation query planner that was premiered in the previous
release continues to work well.
The new query planner has been tweaked slightly
in the current release to help it make better decisions in some
cases, but is largely unchanged. Two new SQL functions, likelihood() and
unlikely(), have been added to allow developers to give hints to the
query planner without forcing the query planner into a particular decision.

Version 3.8.1 is the first SQLite release to take into account the
estimated size of table and index rows when choosing a query plan.
Row size estimates are based on the declared datatypes of columns.
For example, a column of type VARCHAR(1000) is assumed
to use much more space than a column of type INT. The datatype-based
row size estimate can be
overridden by appending a term of the form "sz=NNN" (where NNN is the
average row size in bytes) to the end of the sqlite_stat1.stat
record for a table or index. Currently, row sizes are only used to help the
query planner choose between a table or one of its indices when doing a
table scan or a count(*) operation, though future releases are likely
to use the estimated row size in other contexts as well. The new
PRAGMA stats statement can be used to view row size estimates.

Version 3.8.1 adds the SQLITE_ENABLE_STAT4 compile-time option.
STAT4 is very similar to STAT3 in that it uses samples from indices to
try to guess how many rows of the index will be satisfy by WHERE clause
constraints. The difference is that STAT4 samples all columns of the
index whereas the older STAT3 only sampled the left-most column. Users
of STAT3 are encouraged to upgrade to STAT4. Application developers should
use STAT3 and STAT4 with caution since both options, by design, violate
the query planner stability guarantee, making it more difficult to ensure
uniform performance is widely-deployed and mass-produced embedded
applications.

2013-09-03 - Release 3.8.0.2

SQLite version 3.8.0.2 contains a one-line fix to a bug in the
new optimization that tries to omit unused LEFT JOINs from a query.

2013-08-29 - Release 3.8.0.1

SQLite version 3.8.0.1 fixes some obscure bugs that were uncovered by
users in the 3.8.0 release. Changes from 3.8.0 are minimal.

2013-08-26 - Release 3.8.0

Do not fear the zero!

SQLite version 3.8.0 might easily have been called "3.7.18" instead.
However, this release features the cutover of the
next generation query planner or NGQP, and there is a small chance of
breaking legacy programs that
rely on undefined behavior in previous SQLite releases, and so the
minor version number was incremented for that reason.
But the risks are low and there is a query planner checklist is
available to application developers to aid in avoiding problems.

SQLite version 3.8.0 is actually one of the most heavily tested
SQLite releases ever. Thousands and thousands of beta copies have
be downloaded, and presumably tested, and there have been no problem
reports.

2013-05-20 - Release 3.7.17

SQLite version 3.7.17 is a regularly schedule maintenance release.
Visit the change log for a full explanation of the
changes in this release.

There are many bug fixes in version 3.7.17. But this does not indicate
that 3.7.16 was a problematic release. All of the bugs in 3.7.17 are
obscure and are unlikely to impact any particular application. And most
of the bugs that are fixed in 3.7.17 predate 3.7.16 and have been in
the code for years without ever before being noticed.
Nevertheless, due to the large number of fixes,
all users are encouraged to upgrade when possible.

As far as we know, this bug has never been seen in the wild. The
problem was discovered by the SQLite developers while writing stress tests
for a separate component of SQLite. Those stress tests have not yet
found any problems with the component they were intended to verify, but
they did find the bug which is the subject of this patch release.

Other than updates to version numbers, the only difference between this
release and 3.7.16.1 is a two-character change in a single identifier,
which is contained in the windows-specific OS interface logic. There
are no changes in this release (other than version numbers) for platforms
other than Windows.

2013-03-29 - Release 3.7.16.1

SQLite version 3.7.16.1 is a bug fix release that fixes a few problems
that were present in the previous releases.

The primary motivation for version 3.7.16.1 is to fix a bug in the
query optimizer that was introduced as part of version 3.7.15. The
query optimizer was being a little overzealous in optimizing out some
ORDER BY clauses, which resulted in sorting being omitted on occasions
where sorting is required to get the correct answer. See
ticket a179fe7465 for
details.

In addition to the ORDER BY fix, several other patches to fix obscure
(and mostly harmless) bugs and to fix spelling errors in source code
comments are also included in this release.

2013-03-18 - Release 3.7.16

SQLite version 3.7.16 is a regularly scheduled release of SQLite.
This release contains several language enhancements and improvements
to the query optimizer. A list of the major enhancements and optimizations
can be see on the change log.

There was one important bug fix
(see Ticket fc7bd6358f)
that addresses an incorrect query result that could have occurred in
a three-way join where the join constraints compared INTEGER columns
to TEXT columns. This issue had been in the code for time out of mind
and had never before been reported, so we surmise that it is very obscure.
Nevertheless, all users are advised to upgrade to avoid any future problems
associated with this issue.

2013-01-09 - Release 3.7.15.2

SQLite version 3.7.15.2 is a patch release that fixes a single bug
that was introduced in version version 3.7.15. The fix is a 4-character
edit to a single line of code. Other than this 4-character change and
the update of the version number, nothing has changed from
version 3.7.15.1.

2012-12-19 - Release 3.7.15.1

SQLite version 3.7.15.1 is a patch release that fixes a single bug
that was introduced in version version 3.7.15. The fix involved changing
two lines of code and adding a single assert(). This release also includes
some new test cases to prevent a regression of the bug, and the version
number is increased, of course. But otherwise, nothing has changed from
version 3.7.15.

2012-12-12 - Release 3.7.15

SQLite version 3.7.15 is a regularly schedule release of SQLite. This
release contains several improvements to the query planner and optimizer
and one important bug fix. This is the first release to officially
support Windows 8 Phone.

The important bug fix is a problem that can lead to segfaults when using
shared cache mode on a schema that contains a COLLATE operator within
a CHECK constraint or within a view. Collating functions are associated
with individual database connections. But a pointer to the collating function
was also being cached within expressions. If an expression was part of the
schema and contained a cached collating function, it would point to the
collating function in the database connection that originally parsed the
schema. If that database connection closed while other database
connections using the same shared cache continued to operate, they other
database connections would try to use the deallocated collating function
in the database connection that closed. The fix in version 3.7.15 was to
not cache collating function pointers in the expression structure but
instead look them up each time a new statement is prepared.

This release also contains some important enhancements to the query planner
which should (we hope) make some queries run faster. The enhancements
include:

When doing a full-table scan, try to use an index instead of
the original table, under the theory that indices contain less information
and are thus smaller and hence require less disk I/O to scan.

Do a better job of recognizing when an ORDER BY clause can be
implemented using indices - especially in cases where the ORDER BY clause
contains terms from two or more tables in a join.

2012-10-04 - Release 3.7.14.1

SQLite version 3.7.14.1 is a patch release. Changes from the baseline
version 3.7.14 are minimal and are restricted to fixing three bugs.

One of the fixed bugs is a long-standing issue with the TCL interface.
Another is an external compiler bug that SQLite merely works around and
that only comes up if you are using the VisualStudio-2012 compiler to
generate WinRT applications on ARM with optimizations enabled. The
third problem is an SQLite core bug, introduced in version 3.7.14, that
can cause a segfault if a query contains a LEFT JOIN that contains an OR
in the ON clause.

2012-09-03 - Release 3.7.14

SQLite version 3.7.14 is a regularly scheduled maintenance release
of SQLite. The previous release continues to work well. Upgrading
is optional.

Version 3.7.14 drops native support for OS/2. We are not aware of any
active projects that were using SQLite on OS/2 and since the SQLite
developers had no way of testing on OS/2 it seemed like it was time
to simply remove the OS/2 code from the SQLite tree. If there are
OS/2 projects out there that still need SQLite support, they can
continue to maintain their own private VFS which can be linked to
SQLite at start-time using the sqlite3_vfs_register() interface.

The sqlite3_close_v2() interface has been added. The sqlite3_close_v2()
interface differs from sqlite3_close() in that it is designed to work
better for host language that use a garbage collector. With the older
sqlite3_close() interface, the associated prepared statements and
sqlite3_backup objects must be destroyed before the database connection.
With the newer sqlite3_close_v2() interface, the objects can be destroyed
in any order.

This release also includes performance improvements to the sort algorithm
that is used to implement ORDER BY and CREATE INDEX. And the query planner
has been enhanced to better use covering indices on queries that use OR
terms in the WHERE clause.

2012-06-11 - Release 3.7.13

SQLite version 3.7.13 adds support for WinRT and metro style
applications for Microsoft Windows 8. The 3.7.13 release is
coming sooner than is usual after the previous release in order to get
this new capability into the hands of developers. To use SQLite in
a metro style application, compile with the -DSQLITE_OS_WINRT flag.
Because of the increased application security and safety requirements
of WinRT, all database
filenames should be full pathnames. Note that SQLite is not capable
of accessing databases outside the installation directory and application
data directory. This restriction is another security and safety feature
of WinRT. Apart from these restrictions, SQLite should work exactly
the same on WinRT as it does on every other system.

Also in this release: when a database is opened using URI filenames
and the mode=memory query parameter
then the database is an in-memory database, just as if it had
been named ":memory:". But, if shared cache mode is enabled, then
all other database connections that specify the same URI filename
will connect to the same in-memory database. This allows two or more
database connections (in the same process) to share the same in-memory
database.

This release also includes some corner-case performance optimizations
that are obscure yet significant to an important subset of SQLite users.
Getting these performance optimizations into circulation quickly is
yet another reason for making this release so soon following the previous.

The next release of SQLite is scheduled to occur after the usual
2 or 3 month interval.

2012-05-22 - Patch Release 3.7.12.1

SQLite version 3.7.12.1 is a patch release for version 3.7.12 that
fixes a bug that was
introduced in version 3.7.12 and that can
cause a segfault for certain obscure nested aggregate queries.
There are very few changes in 3.7.12.1, and upgrading is only needed for
applications that do nested aggregate queries.

2012-05-14 - Version 3.7.12

SQLite version 3.7.12 is a regularly scheduled maintenance release.
This release contains several new optimizations and bug fixes and upgrading
is recommended. See the change summary for details.

2012-03-20 - Version 3.7.11

SQLite version 3.7.11 is a regularly scheduled maintenance release
which was rushed out early due to a
bug in the query optimizer
introduced in the previous release. The bug is obscure - it changes
a LEFT JOIN into an INNER JOIN in some cases when there is a 3-way join
and OR terms in the WHERE clause. But it was considered serious enough to
rush out a fix. Apart from this one problem, SQLite version 3.7.10 has
not given any trouble. Upgrading to version 3.7.11 from versions
3.7.6.3, 3.7.7, 3.7.7.1, 3.7.8, or 3.7.9 is
optional. Upgrading from other releases, including the previous release
3.7.10, is recommended.

Other enhancements found in this release are enumerated in the
change log.

2012-01-16 - Version 3.7.10

SQLite version 3.7.10 is a regularly scheduled maintenance release.
Upgrading from version 3.7.6.3, 3.7.7, 3.7.7.1, 3.7.8, or 3.7.9 is
optional. Upgrading from other releases is recommended.

The SQLITE_CONFIG_PCACHE mechanism has been replaced with
SQLITE_CONFIG_PCACHE2. If you do not know what this mechanism
is (it is an extreme corner-case and is seldom used) then this
change will not effect you in the least.

The default schema format number for new database files has changed
from 1 to 4. SQLite has been able to generate and read database files
using schema format 4 for six years. But up unto now, the default
schema format has been 1 so that older versions of SQLite could read
and write databases generated by newer versions of SQLite. But those
older versions of SQLite have become so scarce now that it seems
reasonable to make the new format the default.

SQLite is changing some of the assumptions it makes above the behavior
of disk drives and flash memory devices during a sudden power loss.
This change is completely transparent to applications.
Read about the powersafe overwrite property for additional information.

The PRAGMA cache_size statement has been enhanced. Formerly, you would
use this statement to tell SQLite how many pages of the database files it
should hold in its cache at once. The total memory requirement would
depend on the database page size. Now, if you give PRAGMA cache_size
a negative value -N, it will allocate roughly N
kibibytes of memory to cache,
divided up according to page size. This enhancement allows programs to
more easily control their memory usage.

There have been several obscure bug fixes. One noteworthy bug,
ticket ff5be73dee,
could in theory result in a corrupt database file if a power loss
occurred at just the wrong moment on an unusually cantankerous disk
drive. But that is mostly a theoretical concern and is very unlikely
to happen in practice. The bug was found during laboratory testing
and has never been observed to occur in the wild.

2011-11-01 - Version 3.7.9

SQLite version 3.7.9 is a regularly scheduled maintenance release.
Upgrading from version 3.7.6.3, 3.7.7, 3.7.7.1, and 3.7.8 is optional.
Upgrading from other versions is recommended.

The SQLITE_ENABLE_STAT2 compile-time option is now a no-op. The enhanced
query-planner functionality formerly available using SQLITE_ENABLE_STAT2
is now available through SQLITE_ENABLE_STAT3. The enhanced query planning
is still disabled by default. However, future releases of SQLite might
convert STAT3 from an enable-option to a disable-option so that it is
available by default and is only omitted upon request.

The FTS4 full-text search engine has been enhanced such that tokens in
the search string that begin with "^" must be the first token in their
respective columns in order to match. Formerly, "^" characters in the
search string were simply ignored. Hence, if a legacy application was
including "^" characters in FTS4 search strings, thinking that they would
always be ignored, then those legacy applications might break with this
update. The fix is simply remove the "^" characters from the search
string.

See the change summary for additional changes associated
with this release.

2011-September-19 - Version 3.7.8

SQLite version 3.7.8 is a quarterly maintenance release. Upgrading from
versions 3.7.6.3, 3.7.7, or 3.7.7.1 is optional. Upgrading from other
versions is recommended.

This release features a new "external merge sort" algorithm used to
implement ORDER BY and GROUP BY and also to presort the content of an
index for CREATE INDEX. The new algorithm does approximately the same
number of comparisons and I/Os as before, but the I/Os are much more
sequential and so runtimes are greatly reduced when the size of the
set being sorted is larger than the filesystem cache. The performance
improvement can be dramatic - orders of magnitude faster
for large CREATE INDEX commands. On the other hand,
the code is slightly slower (1% or 2%)
for a small CREATE INDEX. Since CREATE INDEX is not an
operation that commonly occurs on a speed-critical path, we feel that
this tradeoff is a good one. The slight slowdown for small CREATE INDEX
statements might be recovered in a future release. ORDER BY and GROUP BY
operations should now be faster for all cases, large and small.

The query planner has been enhanced to do a better job of handling
the DISTINCT keyword on SELECT statements.

There has been a lot of work on the default VFSes. The unix VFS has
been enhanced to include more overrideable system calls - a feature requested
by Chromium to make it easier to build SQLite into a sandbox. The
windows VFS has been enhanced to be more resistant to interference from
anti-virus software.

Every version of SQLite is better tested than the previous, and 3.7.8
is no exception to this rule. Version 3.7.8 has been used internally by
the SQLite team for mission critical functions and has performed flawlessly.
And, of course, it passes our rigorous testing procedures with no
problems detected. Version 3.7.8 is recommended for all new development.

Upgrading from 3.7.7 is only required for applications that use "PRAGMA
case_sensitive_like" and the sqlite3_prepare() (or sqlite3_exec()) interface.

2011-06-24 - Version 3.7.7

SQLite version 3.7.7 is a regularly scheduled bi-monthly maintenance
release. Upgrading from version 3.7.6.3 is optional. Upgrading from all
prior releases is recommended.

This release adds support for naming database files using URI filenames.
URI filenames are disabled by default (for backwards compatibility) but
applications are encouraged to enable them since incompatibilities are
likely to be exceedingly rare and the feature is useful. See the
URI filename documentation for details.

Most of the other enhancements in this release involve
virtual tables. The virtual table interface has been enhanced to
support SAVEPOINT and ON CONFLICT clause processing, and the built-in
RTREE and FTS3/FTS4 have been augmented to take advantage of
the new capability. This means, for example, that it is now possible
to use the REPLACE command on FTS3/FTS4 and RTREE tables.

The FTS4 full-text index extension has been enhanced to support
the FTS4 prefix option and the FTS4 order option. These two enhancements
are provided in support of search-as-you-type interfaces where search
results begin to appear after the first keystroke in the "search" box
and are refined with each subsequent keystroke. The way this is done is
to do a separate full-text search after each key stroke, and add the
"*" wildcard at the end of the word currently being typed. So, for
example, if the text typed so far is "fast da" and the next character
typed is "t", then the application does a full-text search of the
pattern "fast dat*" and displays the results. Such capability has
always existed. What is new is that the FTS4 prefix option allows
the search to be very fast (a matter of milliseconds) even for difficult
cases such as "t*" or "th*".

There has been a fair amount of work done on the FTS4 module for this
release. But the core SQLite code has changed little and the previous
release has not given any problems, so we expect this to be a very
stable release.

2011-05-19 - Version 3.7.6.3

SQLite version 3.7.6.3 is a patch release that fixes a
single bug
associated with WAL mode. The bug has been in SQLite ever since WAL
was added, but the problem is very obscure and so nobody has noticed
before now. Nevertheless, all users are encouraged to upgrade to
version 3.7.6.3 or later.

The bug is this:
If the cache_size is set very small (less than 10) and SQLite comes
under memory pressure and if a multi-statement transaction is started
in which the last statement prior to COMMIT is a SELECT statement and if
a checkpoint occurs right after the transaction commit, then
it might happen that the transaction will be silently rolled back instead
of being committed.

The default setting for cache_size is 2000. So in most situations, this
bug will never appear. But sometimes programmers set cache_size to
very small values on gadgets and other low-memory devices in order to
save memory space. Such applications are vulnerable.
Note that this bug does not cause database corruption. It is
as if ROLLBACK were being run instead of COMMIT in some cases.

Bug Details

Transactions commit in WAL mode by adding a record onto the end of
the WAL (the write-ahead log) that contains a "commit" flag. So to
commit a transaction, SQLite takes all the pages that have changed
during that transaction, appends them to the WAL, and sets the commit
flag on the last page. Now, if SQLite comes under memory pressure, it
might try to free up memory space by writing changed pages to the WAL
prior to the commit. We call this "spilling" the cache to WAL. There
is nothing wrong with spilling cache to WAL. But if the
memory pressure is severe, it might be that by the time COMMIT is run,
all changed pages for the transaction have already been spilled to WAL
and there are no pages left to be written to WAL.
And with no unwritten pages, there was nothing to put the commit flag
on. And without a commit flag, the transaction would end up being
rolled back.

The fix to this problem was that if all changed pages has already
been written to the WAL when the commit was started, then page 1 of
the database will be written to the WAL again, so that there will always
be a page available on which to set the commit flag.

2011-04-17 - Version 3.7.6.2

SQLite version 3.7.6.2 adds a one-line bug fix to 3.7.6.1 that enables
pthreads to work correctly on NetBSD. The problem was a faulty function
signature for the open system call. The problem does not appear to have
any adverse impact on any system other than NetBSD.

Upgrading from version 3.7.6.1 is only needed on NetBSD.

2011-04-13 - Version 3.7.6.1

SQLite version 3.7.6.1 fixes a single bug in 3.7.6 that can cause a
segfault if SQLITE_FCNTL_SIZE_HINT is used on a unix build that has
SQLITE_ENABLE_LOCKING_MODE set to 0 and is compiled with
HAVE_POSIX_FALLOCATE.

Upgrading from 3.7.6 is only needed for users effected by the
configuration-specific bug described above. There are no other changes
to the code.

2011-04-12 - Version 3.7.6

SQLite version 3.7.6 is a regularly scheduled bi-monthly maintenance
release of SQLite. Upgrading from version 3.7.5 is optional. Upgrading
releases prior to 3.7.5 is recommended.

2011-02-01 - Version 3.7.5

SQLite version 3.7.5 is a regularly scheduled bi-monthly maintenance
release of SQLite. Due to the discovery and fix of
an obscure bug
that could cause database corruption, upgrading from all prior
releases of SQLite is recommended. This bug was found during code
review and has not been observed in the wild.

The output from sqlite3_trace() interface has been enhanced to work
better (and faster) in systems that use recursive extensions such as
FTS3 or RTREE.

Testing with Valgrind shows that this release of SQLite is about 1%
or 2% faster than the previous release for most operations.

A fork of the popular ADO.NET adaptor for SQLite known as System.Data.SQLite
is now available on http://System.Data.SQLite.org/. The originator
of System.Data.SQLite, Robert Simpson, is aware of this fork, has
expressed his approval, and has commit privileges on the new Fossil
repository. The SQLite development team intends to maintain
System.Data.SQLite moving forward.

2010-12-08 - Version 3.7.4

SQLite version 3.7.4 is a regularly scheduled bi-monthly maintenance
release of SQLite. Upgrading from version 3.7.2 and version 3.7.3
is optional. Upgrading from all other SQLite releases is recommended.

This release features full-text search enhancements. The older
FTS3 virtual table is still fully supported, and should also run
faster. In addition, the new FTS4 virtual table is added. FTS4
follows the same syntax as FTS3 but holds additional metadata which
facilitates some performance improvements and more advanced
matchinfo() output. Look for further full-text search enhancements
in subsequent releases.

Also in this release, the EXPLAIN QUERY PLAN output has been enhanced
and new documentation is provided so that application developers can
more easily understand how SQLite is performing their queries.

Thanks to an account from the folks at http://www.devio.us/, OpenBSD
has been added to the list of platforms upon which we
test SQLite prior to every release. That list of platforms
now includes:

Linux x86 & x86_64

MacOS 10.5 & 10.6

MacOS 10.2 PowerPC

WinXP and Win7

Android 2.2

OpenBSD 4.7

The previous release of SQLite (version 3.7.3) has proven to be very
robust. The only serious issue discovered was
ticket 80ba201079 that
describes an incorrect query result that can occur under very
unusual circumstances. The ticket description contains details of the
problem. Suffice it to say here that the problem is very obscure and
is unlikely to effect most applications and so upgrading is optional.
The problem is fixed, of course, in this release.

2010-October-08 - Version 3.7.3

SQLite version 3.7.3 is a regularly scheduled bi-monthly maintenance
release of SQLite. Upgrading from version 3.7.2 is optional.
Upgrading from all other releases is recommended.

This release adds two new interfaces (really just variations on existing
interfaces). The sqlite3_create_function_v2() interface adds a
destructor for the application-data pointer. The new
sqlite3_soft_heap_limit64() interface allows the soft heap limit to
be set to a value greater than 231.

The RTREE extension has been enhanced with the ability to have an
application-defined query region. This might
be used, for example, to locate all objects within
the field of view of a camera.

The 3.7.3 release also includes some performance enhancements, including
query planner improvements, documentation updates,
and fixes to some very obscure bugs.

2010-August-24 - Version 3.7.2

SQLite version 3.7.2 fixes a long-standing bug that can cause the
database free-page list to go corrupt if incremental_vacuum is used
multiple times to
partially reduce the size of a database file that contains many hundreds
of unused database pages. The original bug reports together with links
to the patch that fixes it can be seen
here.

This bug has been in the code for at least a year and possibly longer.
The bug has nothing to do with the versions 3.7.1 or 3.7.0 or any other
recent release. The fact that the bug was discovered (and fixed)
within hours of the 3.7.1 release is purely a coincidence.

The bug is impossible to hit without using incremental_vacuum and is
very difficult to hit even with incremental_vacuum. And the kind of
corruption that the bug causes can usually be fixed
simply by running VACUUM. Nevertheless, because the bug can result
in database corruption, it is recommended that all SQLite users upgrade
to version 3.7.2 or later.

2010-August-23 - Version 3.7.1

SQLite version 3.7.1 is a stabilization release for the 3.7.x series.
Other than the filesize-in-header bug that was fixed in version 3.7.0.1,
no major problems have been seen in 3.7.0. Some minor corner-case
performance regressions have been fixed. A typo in the OS/2 interface
has been repaired.

A biggest part of the 3.7.1 release is a cleanup and refactoring of
the pager module within SQLite. This refactoring should have no
application-visible effects. The purpose was to reorganize the code
in ways that make it easier to prove correctness.

The 3.7.1 release adds new experimental methods for obtained more
detailed memory usage information and for controlling database file
fragmentation. And the query planner now does a better job of
optimizing the LIKE and GLOB operators.

This release increases the maximum size of database pages from 32KiB to
64KiB. A database with 64KiB pages will not be readable or writable by
older versions of SQLite. Note that further increases in page size
are not feasible since the file format uses 16-bit offsets to structures
within each page.

2010-August-04 - Version 3.7.0.1

SQLite version 3.7.0.1 is a patch release to fix a bug in the new
filesize-in-header feature of the SQLite file format
that could cause database corruption if the same database file is
written alternately with version 3.7.0 and version 3.6.23.1 or earlier.
A performance regression was also fixed in this release.

2010-07-22 - Version 3.7.0

SQLite version 3.7.0 is a major release of SQLite that features
a new transaction control mechanism using a write-ahead log or WAL.
The traditional rollback-journal is still used as the default so there
should be no visible change for legacy programs. But newer programs
can take advantage of improved performance and concurrency by enabling
the WAL journaling mode.

SQLite version 3.7.0 also contains some query planner enhancements and
a few obscure bug fixes, but the only really big change is the addition
of WAL mode.

2010-03-30 - Version 3.6.23.1

SQLite version 3.6.23.1 is a patch release to fix a bug in the
offsets() function of FTS3 at the request of the Mozilla.

2010-03-09 - Version 3.6.23

SQLite version 3.6.23 is a regular bimonthly release of SQLite.
Upgrading from the prior release is purely optional.

2010-01-06 - Version 3.6.22

SQLite version 3.6.22 is a bug-fix release. Two bugs have been fixed
that might cause incorrect query results.

Ticket 31338dca7e
describes a
problem with queries that have a WHERE clause of the form (x AND y) OR z
where x and z come from one table of a join and y comes from a different
table.

Ticket eb5548a849
describes
a problem where the use of the CAST operator in the WHERE clause can lead
to incorrect results if the column being cast to a new datatype is also
used in the same WHERE clause without being cast.

Both bugs are obscure,
but because they could arise in an application after deployment, it is
recommended that all applications upgrade SQLite to version 3.6.22.

This release also includes other minor bug fixes and performance
enhancements, especially in the FTS3 extension.

2009-12-07 - Version 3.6.21

SQLite version 3.6.21 focuses on performance optimization. For
a certain set of traces, this version uses 12% fewer CPU instructions
than the previous release (as measured by Valgrind). In addition, the
FTS3 extension has been through an extensive cleanup and rework and
the sqlite3_trace() interface has been modified to insert
bound parameter values into its output.

2009-11-04 - Version 3.6.20

SQLite version 3.6.20 is a general maintenance release. The
query planner has been enhanced to work better with bound parameters
in LIKE and GLOB operators and in range constraints and various minor
bugs have been fixed. Upgrading from 3.6.19 is optional.

Version 3.6.19 also adds support for the
IS and IS NOT operators. Formerly, SQLite (as most
other SQL database engines) supported IS NULL and IS NOT NULL. The
IS and IS NOT operators are generalizations that allow the right-hand
side to be an arbitrary expression. IS and IS NOT work the same as
== (equals) and != (not equals) except that with IS and IS NOT the
NULL values compare equal to one another.

2009-09-11 - Version 3.6.18

Beginning with this release, the SQLite source code is tracked and
managed using the Fossil
distributed configuration management system. SQLite was previously
versioned using CVS. The entire CVS history has been imported into
Fossil. The older CVS repository remains on the website but is
read-only.

There are two major enhancements in SQLite version 3.6.18. The first
is a series or refinements to the query planner that help SQLite to
choose better plans for joins where in the past it was selecting suboptimal
query plans. The SQLITE_ENABLE_STAT2 compile-time option has been
added to cause SQLite to collect histogram data on indices when the
ANALYZE command is run. The use of histograms improve the query
planning performance even more.

The second major enhancement is that SQLite now support recursive
triggers. The older non-recursive behavior of triggers is still the
default behavior. Recursive triggers are activated using the
recursive_triggers pragma. In addition to allowing triggers to
call themselves (either directly or indirectly) the new capability
also fires DELETE triggers on rows that are removed from a table
as a result of REPLACE conflict resolution processing.

Non-recursive triggers are still the default behavior since this
is least likely to cause problems for existing applications. However,
we anticipate that triggers will become
recursive by default beginning with release 3.7.0. At that point,
applications that want to continue using the older non-recursive
trigger behavior will need to use the recursive_triggers pragma
to disable recursive triggers.

This version of SQLite also contains bug fixes, though none of the
bugs are serious and all are obscure, so upgrading is optional.

The SQLite core continues to have 100% branch test coverage
and so despite the many changes in this release, the developers
believe that this version of SQLite is stable and ready for production
use.

2009-08-10 - Version 3.6.17

This is a monthly maintenance release with a focus of bug fixes,
performance improvements, and increased test coverage. This is the
first release of SQLite since 100% branch test coverage
was achieved on the SQLite core.

In addition, a new interface sqlite3_strnicmp() is provided for the
convenience of extension writers.

None of the bugs fixed in this release are serious. All bugs are
obscure. Upgrading is optional.

2009-07-25 - 100% Branch Test Coverage

A subset of the TH3 test suite was measured by gcov to provide
100% branch test coverage over the SQLite core
(exclusive of the VFS backend and of extensions such as FTS3 and RTREE)
when compiled for SuSE 10.1 Linux on x86. The SQLite developers pledge
to maintain branch test coverage at 100% in all future releases.
Ongoing work will strive for 100% branch test coverage on the
operating-system backends and extensions as well.

2009-06-27 - Version 3.6.16

SQLite version 3.6.16 is another general maintenance release containing
performance and robustness enhancements. A single notable bug was fixed
(ticket #3929). This bug cause cause INSERT or UPDATE statements to fail
on indexed tables that have AFTER triggers that modify the same table and
index.

2009-06-15 - Version 3.6.15

SQLite version 3.6.15 is a general maintenance release containing
performance and robustness enhancements and fixes for various obscure
bugs.

2009-05-25 - Version 3.6.14.2

SQLite version 3.6.14.2 fixes an obscure bug in the code generator
(ticket #3879)
section of SQLite which can potentially cause incorrect query results.
The changes from the prior release consist of only this one bug fix,
check-in [6676]
and a change to the version number text.

The bug was introduced in version 3.6.14. It is recommended that
users of version 3.6.14 and 3.6.14.1 upgrade to this release. Applications
are unlikely to hit this bug, but since it is difficult to predict which
applications might hit it and which might not, we recommend that all
users of 3.6.14 and 3.5.14.1 upgrade to this release.

2009-05-19 - Version 3.6.14.1

SQLite version 3.6.14.1 is a patch release to version 3.6.14 with
minimal changes that fixes three bugs. Upgrading is only necessary
for users who are impacted by one or more of those bugs.

2009-05-07 - Version 3.6.14

SQLite version 3.6.14 provides new performance enhancements in
the btree and pager layers and in the query optimizer. Certain
workloads can be as much as twice as fast as the previous release,
though 10% faster is a more typical result.

Queries against virtual tables that contain OR and IN operators
in the WHERE clause are now able to use indexing.

A new optional asynchronous I/O backend is available for
unix and windows. The asynchronous backend gives the illusion of faster
response time by pushing slow write operations into a background thread.
The tradeoff for faster response time is that more memory is required
(to hold the content of the pending writes) and if a power failure or
program crash occurs, some transactions that appeared to have committed
might end up being rolled back upon restart.

This release also contains many minor bug fixes, documentation enhancements,
new test cases, and cleanups and simplifications to the source code.

There is no compelling reason to upgrade from versions 3.6.12 or
3.6.13 if those prior versions are working. Though many users may
benefit from the improved performance.

2008-12-16 - Version 3.6.7

SQLite version 3.6.7 contains a major cleanup of the Unix driver,
and support for the new Proxy Locking mechanism on Mac OS X. Though
the Unix driver is reorganized, its functionality is the same and so
applications should not notice a difference.

2008-11-26 - Version 3.6.6.2

This release fixes a bug that was introduced into SQLite version 3.6.6
and which seems like it might be able to cause database corruption. This
bug was detected during stress testing. It has not been seen in the wild.
An analysis of the problem suggests that the bug might be able to cause
database corruption, however focused efforts to find a real-world test
cases that actually causes database corruption have so far been unsuccessful.
Hence, the likelihood of this bug causing problems is low. Nevertheless,
we have decided to do an emergency branch release out of an abundance of
caution.

The version 3.6.6.2 release also fixes an obscure memory leak that
can occur following a disk I/O error.

2008-11-22 - Version 3.6.6.1

This release fixes a bug that was introduced into SQLite version 3.6.4
and that can cause database corruption in obscure cases. This bug has
never been seen in the wild; it was first detected by internal stress
tests and required substantial analysis before it could be shown to
potentially lead to corruption. So we feel that SQLite versions 3.6.4,
3.6.5, and 3.6.6 are safe to use for development work. But upgrading
to this patch release or later is recommended prior to deploying
products that incorporate SQLite.

We have taken the unusual step of issuing a patch release in order to
get the fix for this bug into circulation quickly. SQLite version 3.6.7
will continue on its normal path of development with an anticipated
release in mid December.

2008-11-19 - Version 3.6.6

SQLite version 3.6.5 is released. This is a quick turn-around release
that fixes a bug in virtual tables and FTS3 that snuck into
version 3.6.5. This release also adds the new
application-defined page cache mechanism.

2008-11-12 - Version 3.6.5

SQLite version 3.6.5 is released. There are various minor feature
enhancements and numerous obscure bug fixes.
The change log contains the details. Upgrading is
optional.

2008-11-01 - Bloomberg Joins SQLite Consortium

2008-10-15 - Version 3.6.4

SQLite version 3.6.4 adds new features designed to help applications
detect when indices are not being used on query. There are also some
important performance improvements. Upgrading is optional.

2008-09-22 - Version 3.6.3

SQLite version 3.6.3 fixes a bug in SELECT DISTINCT that was introduced
by the previous version. No new features are added. Upgrading is
recommended for all applications that make use of DISTINCT.

2008-08-30 - Version 3.6.2

SQLite version 3.6.2 contains rewrites of the page-cache subsystem and
the procedures for matching identifiers to table columns in SQL statements.
These changes are designed to better modularize the code and make it more
maintainable and reliable moving forward. Nearly 5000 non-comment lines
of core code (about 11.3%) have changed
from the previous release. Nevertheless, there should be no
application-visible changes, other than bug fixes.

2008-08-06 - Version 3.6.1

SQLite version 3.6.1 is a stabilization and performance enhancement
release.

2008-07-16 - Version 3.6.0 beta

Version 3.6.0 makes changes to the VFS object in order
to make SQLite more easily portable to a wider variety of platforms.
There are potential incompatibilities with some legacy applications.
See the 35to36.html document for details.

Many new interfaces are introduced in version 3.6.0. The code is
very well tested and is appropriate for use in stable systems. We
have attached the "beta" designation only so that we can make tweaks to
the new interfaces in the next release without having to declare an
incompatibility.

2008-05-12 - Version 3.5.9

Version 3.5.9 adds a new experimental PRAGMA: journal_mode.
Setting the journal mode to PERSIST can provide performance improvement
on systems where deleting a file is expensive. The PERSIST journal
mode is still considered experimental and should be used with caution
pending further testing.

Version 3.5.9 is intended to be the last stable release prior to
version 3.6.0. Version 3.6.0 will make incompatible changes to the
sqlite3_vfs VFS layer in order to address deficiencies in the original
design. These incompatibilities will only effect programmers who
write their own custom VFS layers (typically embedded device builders).
The planned VFS changes will be much smaller
than the changes that occurred on the
3.4.2 to 3.5.0 transaction that occurred last
September.

This release of SQLite is considered stable and ready for production use.

2008-04-16 - Version 3.5.8

Version 3.5.8 includes some important new performance optimizations
in the virtual machine code generator, including constant subexpression
factoring and common subexpression elimination. This release also
creates new public interfaces:
sqlite3_randomness() provides access to SQLite's internal
pseudo-random number generator, sqlite3_limit() allows size
limits to be set at run-time on a per-connection basis, and
sqlite3_context_db_handle() is a convenience routine that allows
an application-defined SQL function implementation to retrieve
its database connection handle.

This release of SQLite is considered stable and ready for production use.

2008-03-17 - Version 3.5.7

Version 3.5.7 fixes several minor and obscure bugs, especially
in the autoconf-generated makefile. Upgrading is optional.
This release of SQLite is considered stable and ready for production use.

2008-02-06 - Version 3.5.6

Version 3.5.6 fixes a minor regression in 3.5.5 - a regression that
had nothing to do with the massive change of the virtual machine
to a register-based design.
No problems have been reported with the new virtual machine. This
release of SQLite is considered stable and ready for production use.

2008-01-31 - Version 3.5.5

Version 3.5.5 changes over 8% of the core source code of SQLite in order
to convert the internal virtual machine from a stack-based design into
a register-based design. This change will allow future optimizations
and will avoid an entire class of stack overflow bugs that have caused
problems in the past. Even though this change is large, extensive testing
has found zero errors in the new virtual machine and so we believe this
to be a very stable release.

2007-12-14 - Version 3.5.4

Version 3.5.4 fixes a long-standing but obscure bug in UPDATE and
DELETE which might cause database corruption. (See ticket #2832.)
Upgrading is recommended for all users.

This release also brings the processing of ORDER BY statements into
compliance with standard SQL. This could, in theory, cause problems
for existing applications that depend on the older, buggy behavior.
See ticket #2822 for additional information.

2007-11-27 - Version 3.5.3

This is an incremental release that fixes several minor problems.
Upgrading is optional. If Version 3.5.2 or 3.5.1 is working fine
for you, then there is no pressing need to change to 3.5.3.

The prebuilt binaries and the amalgamation found on the
download page include the FTS3 fulltext
search extension module. We are doing this on an experimental
basis and are not promising to provide prebuilt binaries with
FTS3 in the future.

2007-11-05 - Version 3.5.2

This is an incremental release that fixes several minor problems,
adds some obscure features, and provides some performance tweaks.
Upgrading is optional.

The experimental compile-time option
SQLITE_OMIT_MEMORY_ALLOCATION is no longer supported. On the other
hand, it is now possible to compile SQLite so that it uses a static
array for all its dynamic memory allocation needs and never calls
malloc. Expect to see additional radical changes to the memory
allocation subsystem in future releases.

2007-10-04 - Version 3.5.1

Fix a long-standing bug that might cause database corruption if a
disk-full error occurs in the middle of a transaction and that
transaction is not rolled back.
Ticket #2686.

The new VFS layer is stable. However, we still reserve the right to
make tweaks to the interface definition of the VFS if necessary.

2007-09-04 - Version 3.5.0 alpha

The OS interface layer and the memory allocation subsystems in
SQLite have been reimplemented. The published API is largely unchanged
but the (unpublished) OS interface has been modified extensively.
Applications that implement their own OS interface will require
modification. See
34to35.html for details.

This is a large change. Approximately 10% of the source code was
modified. We are calling this first release "alpha" in order to give
the user community time to test and evaluate the changes before we
freeze the new design.

2007-06-18 - Version 3.4.0

This release fixes two separate bugs either of which
can lead to database corruption. Upgrading
is strongly recommended. If you must continue using an older version
of SQLite, please at least read about how to avoid these bugs
at
CorruptionFollowingBusyError and
ticket #2418

This release also adds explicit limits on the
sizes and quantities of things SQLite will handle. The new limits might
causes compatibility problems for existing applications that
use excessively large strings, BLOBs, tables, or SQL statements.
The new limits can be increased at compile-time to work around any problems
that arise. Nevertheless, the version number of this release is
3.4.0 instead of 3.3.18 in order to call attention to the possible
incompatibility.

2007-04-25 - Version 3.3.17

This version fixes a bug in the forwards-compatibility logic of SQLite
that was causing a database to become unreadable when it should have
been read-only. Upgrade from 3.3.16 only if you plan to deploy into
a product that might need to be upgraded in the future. For day to day
use, it probably does not matter.

2007-04-18 - Version 3.3.16

Performance improvements added in 3.3.14 but mistakenly turned off
in 3.3.15 have been reinstated. A bug has been fixed that prevented
VACUUM from running if a NULL value was in a UNIQUE column.

2007-04-09 - Version 3.3.15

An annoying bug introduced in 3.3.14 has been fixed. There are
also many enhancements to the test suite.

2007-04-02 - Version 3.3.14

This version focuses on performance improvements. If you recompile
the amalgamation using GCC option -O3 (the precompiled binaries
use -O2) you may see performance
improvements of 35% or more over version 3.3.13 depending on your
workload. This version also
adds support for
exclusive access mode.

2007-02-13 - Version 3.3.13

This version fixes a subtle bug in the ORDER BY optimizer that can
occur when using joins. There are also a few minor enhancements.
Upgrading is recommended.

2007-01-27 - Version 3.3.12

The first published build of the previous version used the wrong
set of source files. Consequently, many people downloaded a build
that was labeled as "3.3.11" but was really 3.3.10. Version 3.3.12
is released to clear up the ambiguity. A couple more bugs have
also been fixed and
PRAGMA integrity_check has been enhanced.

2007-01-22 - Version 3.3.11

Version 3.3.11 fixes for a few more problems in version 3.3.9 that
version 3.3.10 failed to catch. Upgrading is recommended.

2007-01-09 - Version 3.3.10

Version 3.3.10 fixes several bugs that were introduced by the previous
release. Upgrading is recommended.

2007-01-04 - Version 3.3.9

Version 3.3.9 fixes bugs that can lead to database corruption under
obscure and difficult to reproduce circumstances. See
DatabaseCorruption in the
wiki for details.
This release also adds the new
sqlite3_prepare_v2()
API and includes important bug fixes in the command-line
shell and enhancements to the query optimizer. Upgrading is
recommended.

2006-10-09 - Version 3.3.8

Version 3.3.8 adds support for full-text search using the
FTS1
module. There are also minor bug fixes. Upgrade only if
you want to try out the new full-text search capabilities or if
you are having problems with 3.3.7.

2006-08-12 - Version 3.3.7

Version 3.3.7 includes support for loadable extensions and virtual
tables. But both features are still considered "beta" and their
APIs are subject to change in a future release. This release is
mostly to make available the minor bug fixes that have accumulated
since 3.3.6. Upgrading is not necessary. Do so only if you encounter
one of the obscure bugs that have been fixed or if you want to try
out the new features.

2006-06-19 - New Book About SQLite

The Definitive Guide to SQLite,
a new book by
Mike Owens
is now available from Apress.
The books covers the latest SQLite internals as well as
the native C interface and bindings for PHP, Python,
Perl, Ruby, Tcl, and Java. Recommended.

2006-06-6 - Version 3.3.6

Changes include improved tolerance for Windows virus scanners
and faster :memory: databases. There are also fixes for several
obscure bugs. Upgrade if you are having problems.

2006-04-5 - Version 3.3.5

This release fixes many minor bugs and documentation typos and
provides some minor new features and performance enhancements.
Upgrade only if you are having problems or need one of the new features.

2006-02-11 - Version 3.3.4

This release fixes several bugs, including a
blunder that might cause a deadlock on multithreaded systems.
Anyone using SQLite in a multithreaded environment should probably upgrade.

2006-01-31 - Version 3.3.3 stable

There have been no major problems discovered in version 3.3.2, so
we hereby declare the new APIs and language features to be stable
and supported.

2006-01-24 - Version 3.3.2 beta

More bug fixes and performance improvements as we move closer to
a production-ready version 3.3.x.

2006-01-16 - Version 3.3.1 alpha

Many bugs found in last week's alpha release have now been fixed and
the library is running much faster again.

Database connections can now be moved between threads as long as the
connection holds no locks at the time it is moved. Thus the common
paradigm of maintaining a pool of database connections and handing
them off to transient worker threads is now supported.
Please help test this new feature.
See
the MultiThreading wiki page for additional
information.

2006-01-10 - Version 3.3.0 alpha

Version 3.3.0 adds support for CHECK constraints, DESC indices,
separate REAL and INTEGER column affinities, a new OS interface layer
design, and many other changes. The code passed a regression
test but should still be considered alpha. Please report any
problems.

The file format for version 3.3.0 has changed slightly to support
descending indices and
a more efficient encoding of boolean values. SQLite 3.3.0 will read and
write legacy databases created with any prior version of SQLite 3. But
databases created by version 3.3.0 will not be readable or writable
by earlier versions of the SQLite. The older file format can be
specified at compile-time for those rare cases where it is needed.

2005-12-19 - Versions 3.2.8 and 2.8.17

These versions contain one-line changes to 3.2.7 and 2.8.16 to fix a bug
that has been present since March of 2002 and version 2.4.0.
That bug might possibly cause database corruption if a large INSERT or
UPDATE statement within a multi-statement transaction fails due to a
uniqueness constraint but the containing transaction commits.

2005-09-24 - Version 3.2.7

This version fixes several minor and obscure bugs.
Upgrade only if you are having problems.

2005-09-16 - Version 3.2.6 - Critical Bug Fix

This version fixes a bug that can result in database
corruption if a VACUUM of a 1 gigabyte or larger database fails
(perhaps do to running out of disk space or an unexpected power loss)
and is later rolled back.

Also in this release:
The ORDER BY and GROUP BY processing was rewritten to use less memory.
Support for COUNT(DISTINCT) was added. The LIKE operator can now be
used by the optimizer on columns with COLLATE NOCASE.

2005-08-27 - Version 3.2.5

This release fixes a few more lingering bugs in the new code.
We expect that this release will be stable and ready for production use.

2005-08-24 - Version 3.2.4

This release fixes a bug in the new optimizer that can lead to segfaults
when parsing very complex WHERE clauses.

2005-08-21 - Version 3.2.3

This release adds the ANALYZE command,
the CAST operator, and many
very substantial improvements to the query optimizer. See the
change log for additional
information.

2005-08-02 - 2005 Open Source Award for SQLite

SQLite and its primary author D. Richard Hipp have been honored with
a 2005 Open Source Award
from Google and O'Reilly.

2005-06-13 - Version 3.2.2

This release includes numerous minor bug fixes, speed improvements,
and code size reductions. There is no reason to upgrade unless you
are having problems or unless you just want to.

2005-03-29 - Version 3.2.1

2005-03-21 - Version 3.2.0

The primary purpose for version 3.2.0 is to add support for
ALTER TABLE ADD COLUMN.
The new ADD COLUMN capability is made
possible by AOL developers supporting and embracing great
open-source software. Thanks, AOL!

Version 3.2.0 also fixes an obscure but serious bug that was discovered
just prior to release. If you have a multi-statement transaction and
within that transaction an UPDATE or INSERT statement fails due to a
constraint, then you try to rollback the whole transaction, the rollback
might not work correctly. See
Ticket #1171
for details. Upgrading is recommended for all users.

2005-03-16 - Version 3.1.6

Version 3.1.6 fixes a critical bug that can cause database corruption
when inserting rows into tables with around 125 columns. This bug was
introduced in version 3.0.0. See
Ticket #1163
for additional information.

2005-03-11 - Versions 3.1.4 and 3.1.5 Released

Version 3.1.4 fixes a critical bug that could cause database corruption
if the autovacuum mode of version 3.1.0 is turned on (it is off by
default) and a CREATE UNIQUE INDEX is executed within a transaction but
fails because the indexed columns are not unique. Anyone using the
autovacuum feature and unique indices should upgrade.

Version 3.1.5 adds the ability to disable
the F_FULLFSYNC ioctl() in OS-X by setting "PRAGMA synchronous=on" instead
of the default "PRAGMA synchronous=full". There was an attempt to add
this capability in 3.1.4 but it did not work due to a spelling error.

2005-02-19 - Version 3.1.3 Released

Version 3.1.3 cleans up some minor issues discovered in version 3.1.2.

2005-02-15 - Versions 2.8.16 and 3.1.2 Released

A critical bug in the VACUUM command that can lead to database
corruption has been fixed in both the 2.x branch and the main
3.x line. This bug has existed in all prior versions of SQLite.
Even though it is unlikely you will ever encounter this bug,
it is suggested that all users upgrade. See
ticket #1116. for additional information.

Version 3.1.2 is also the first stable release of the 3.1
series. SQLite 3.1 features added support for correlated
subqueries, autovacuum, autoincrement, ALTER TABLE, and
other enhancements. See the
release notes
for version 3.1.0 for a detailed description of the
changes available in the 3.1 series.

2005-02-01 - Version 3.1.1 (beta) Released

Version 3.1.1 (beta) is now available on the
website. Version 3.1.1 is fully backwards compatible with the 3.0 series
and features many new features including Autovacuum and correlated
subqueries. The
release notes
From version 3.1.0 apply equally to this release beta. A stable release
is expected within a couple of weeks.

2005-01-21 - Version 3.1.0 (alpha) Released

Version 3.1.0 (alpha) is now available on the
website. Version 3.1.0 is fully backwards compatible with the 3.0 series
and features many new features including Autovacuum and correlated
subqueries. See the
release notes
for details.

This is an alpha release. A beta release is expected in about a week
with the first stable release to follow after two more weeks.

2004-11-09 - SQLite at the 2004 International PHP Conference

There was a talk on the architecture of SQLite and how to optimize
SQLite queries at the 2004 International PHP Conference in Frankfurt,
Germany.
Slides from that talk are available.

2004-10-11 - Version 3.0.8

Version 3.0.8 of SQLite contains several code optimizations and minor
bug fixes and adds support for DEFERRED, IMMEDIATE, and EXCLUSIVE
transactions. This is an incremental release. There is no reason
to upgrade from version 3.0.7 if that version is working for you.

2004-09-18 - Version 3.0.7

Version 3.0 has now been in use by multiple projects for several
months with no major difficulties. We consider it stable and
ready for production use.

2004-09-02 - Version 3.0.6 (beta)

Because of some important changes to sqlite3_step(),
we have decided to
do an additional beta release prior to the first "stable" release.
If no serious problems are discovered in this version, we will
release version 3.0 "stable" in about a week.

2004-08-29 - Version 3.0.5 (beta)

The fourth beta release of SQLite version 3.0 is now available.
The next release is expected to be called "stable".

2004-08-08 - Version 3.0.4 (beta)

The third beta release of SQLite version 3.0 is now available.
This new beta fixes several bugs including a database corruption
problem that can occur when doing a DELETE while a SELECT is pending.
Expect at least one more beta before version 3.0 goes final.

2004-07-22 - Version 3.0.3 (beta)

The second beta release of SQLite version 3.0 is now available.
This new beta fixes many bugs and adds support for databases with
varying page sizes. The next 3.0 release will probably be called
a final or stable release.

Version 3.0 adds support for internationalization and a new
more compact file format.
Details.
The API and file format have been fixed since 3.0.2. All
regression tests pass (over 100000 tests) and the test suite
exercises over 95% of the code.

SQLite version 3.0 is made possible in part by AOL
developers supporting and embracing great Open-Source Software.

2004-07-22 - Version 2.8.15

SQLite version 2.8.15 is a maintenance release for the version 2.8
series. Version 2.8 continues to be maintained with bug fixes, but
no new features will be added to version 2.8. All the changes in
this release are minor. If you are not having problems, there is
there is no reason to upgrade.

2004-06-30 - Version 3.0.2 (beta) Released

The first beta release of SQLite version 3.0 is now available.
Version 3.0 adds support for internationalization and a new
more compact file format.
Details.
As of this release, the API and file format are frozen. All
regression tests pass (over 100000 tests) and the test suite
exercises over 95% of the code.

SQLite version 3.0 is made possible in part by AOL
developers supporting and embracing great Open-Source Software.

2004-06-25 - Website hacked

The www.sqlite.org website was hacked sometime around 2004-06-22
because the lead SQLite developer failed to properly patch CVS.
Evidence suggests that the attacker was unable to elevate privileges
above user "cvs". Nevertheless, as a precaution the entire website
has been reconstructed from scratch on a fresh machine. All services
should be back to normal as of 2004-06-28.

2004-06-18 - Version 3.0.0 (alpha) Released

The first alpha release of SQLite version 3.0 is available for
public review and comment. Version 3.0 enhances internationalization support
through the use of UTF-16 and user-defined text collating sequences.
BLOBs can now be stored directly, without encoding.
A new file format results in databases that are 25% smaller (depending
on content). The code is also a little faster. In spite of the many
new features, the library footprint is still less than 240KB
(x86, gcc -O1).
Additional information.

Our intent is to freeze the file format and API on 2004-07-01.
Users are encouraged to review and evaluate this alpha release carefully
and submit any feedback prior to that date.

The 2.8 series of SQLite will continue to be supported with bug
fixes for the foreseeable future.

2004-06-09 - Version 2.8.14 Released

SQLite version 2.8.14 is a patch release to the stable 2.8 series.
There is no reason to upgrade if 2.8.13 is working ok for you.
This is only a bug-fix release. Most development effort is
going into version 3.0.0 which is due out soon.

2004-05-31 - CVS Access Temporarily Disabled

Anonymous access to the CVS repository will be suspended
for 2 weeks beginning on 2004-06-04. Everyone will still
be able to download
prepackaged source bundles, create or modify trouble tickets, or view
change logs during the CVS service interruption. Full open access to the
CVS repository will be restored on 2004-06-18.

2004-04-23 - Work Begins On SQLite Version 3

Work has begun on version 3 of SQLite. Version 3 is a major
changes to both the C-language API and the underlying file format
that will enable SQLite to better support internationalization.
The first beta is schedule for release on 2004-07-01.

Plans are to continue to support SQLite version 2.8 with
bug fixes. But all new development will occur in version 3.0.